---
title: "Errors and retries"
description: "HTTP status semantics and the retry rules that prevent duplicate effects."
---

> Documentation Index
> Fetch the complete documentation index at: https://help.tooluse.net/llms.txt
> Use this file to discover all available pages before exploring further.

# Errors and retries

<h2 id="status-codes">Status codes</h2>
<table>
<thead>
<tr>
<th>Status</th>
<th>Meaning</th>
<th>Caller action</th>
</tr>
</thead>
<tbody>
<tr>
<td><code>400</code></td>
<td>Invalid input or device authorization polling state</td>
<td>Correct the request or branch on the device error code</td>
</tr>
<tr>
<td><code>401</code></td>
<td>Missing, expired, revoked, or invalid credential</td>
<td>Reauthenticate; do not retry unchanged</td>
</tr>
<tr>
<td><code>402</code></td>
<td>Managed credit cannot cover the reservation</td>
<td>Add credit or use a BYO connection</td>
</tr>
<tr>
<td><code>403</code></td>
<td>Authenticated but not permitted</td>
<td>Change role, scope, or operation configuration</td>
</tr>
<tr>
<td><code>404</code></td>
<td>Resource absent or intentionally hidden across an app boundary</td>
<td>Verify the application and resource ID</td>
</tr>
<tr>
<td><code>409</code></td>
<td>Stale revision, idempotency conflict, or invalid state transition</td>
<td>Read current state before deciding</td>
</tr>
<tr>
<td><code>422</code></td>
<td>Workflow or schema refused</td>
<td>Correct the YAML, task type, or input</td>
</tr>
<tr>
<td><code>429</code></td>
<td>Admission limit reached</td>
<td>Honor the limit; retry only after capacity returns</td>
</tr>
<tr>
<td><code>5xx</code></td>
<td>Tooluse.net or an upstream dependency failed</td>
<td>Retry a safe read with backoff; reconcile uncertain effects</td>
</tr>
</tbody>
</table>
<h2 id="retry-rule">Retry rule</h2>
<p>Never retry a write by inventing a new idempotency key after an ambiguous response. Reuse the original key to recover the recorded result, or reconcile the original attempt when its outcome is <code>UNKNOWN</code>.</p>
<h2 id="see-also">See also</h2>
<ul>
<li><a href="/operate/troubleshooting">Troubleshooting</a></li>
<li><a href="/reference/identifiers">Identifiers, states, and limits</a></li>
</ul>

Source: https://help.tooluse.net/operate/errors/index.mdx